Electrocatalysts of the hydrogen evolution and oxidation reactions (HER and HOR) are of critical importance for the realization of future hydrogen economy. In order to make electrocatalysts ...economically competitive for large-scale applications, increasing attention has been devoted to developing noble metal-free HER and HOR electrocatalysts especially for alkaline electrolytes due to the promise of emerging hydroxide exchange membrane fuel cells. Herein, we report that interface engineering of Ni
N and Ni results in a unique Ni
N/Ni electrocatalyst which exhibits exceptional HER/HOR activities in aqueous electrolytes. A systematic electrochemical study was carried out to investigate the superior hydrogen electrochemistry catalyzed by Ni
N/Ni, including nearly zero overpotential of catalytic onset, robust long-term durability, unity Faradaic efficiency, and excellent CO tolerance. Density functional theory computations were performed to aid the understanding of the electrochemical results and suggested that the real active sites are located at the interface between Ni
N and Ni.
This paper proposes a novel local feature descriptor, called a local feature statistics histogram (LFSH), for efficient 3D point cloud registration. An LFSH forms a comprehensive description of local ...shape geometries by encoding their statistical properties on local depth, point density, and angles between normals. The sub-features in the LFSH descriptor are low-dimensional and quite efficient to compute. In addition, an optimized sample consensus (OSAC) algorithm is developed to iteratively estimate the optimum transformation from point correspondences. OSAC can handle the challenging cases of matching highly self-similar models. Based on the proposed LFSH and OSAC, a coarse-to-fine algorithm can be formed for 3D point cloud registration. Experiments and comparisons with the state-of-the-art descriptors demonstrate that LFSH is highly discriminative, robust, and significantly faster than other descriptors. Meanwhile, the proposed coarse-to-fine registration algorithm is demonstrated to be robust to common nuisances, including noise and varying point cloud resolutions, and can achieve high accuracy on both model data and scene data.
The local reference frame (LRF), as an independent coordinate system constructed on the local 3D surface, is broadly employed in 3D local feature descriptors. The benefits of the LRF include ...rotational invariance and full 3D spatial information, thereby greatly boosting the distinctiveness of a 3D feature descriptor. There are numerous LRF methods in the literature; however, no comprehensive study comparing their repeatability and robustness performance under different application scenarios and nuisances has been conducted. This paper evaluates eight state-of-the-art LRF proposals on six benchmarks with different data modalities (e.g., LiDAR, Kinect, and Space Time) and application contexts (e.g., shape retrieval, 3D registration, and 3D object recognition). In addition, the robustness of each LRF to a variety of nuisances, including varying support radii, Gaussian noise, outliers (shot noise), mesh resolution variation, distance to boundary, keypoint localization error, clutter, occlusion, and partial overlap, is assessed. The experimental study also measures the performance under different keypoint detectors, descriptor matching performance when using different LRFs and feature representation combinations, as well as computational efficiency. Considering the evaluation outcomes, we summarize the traits, advantages, and current limitations of the tested LRF methods.
It is obtained that a localization of the vorticity direction coherence conditions for the regularity of the 3D shear thickening fluids to an arbitrarily small space-time cylinder. It implies the ...regularity of any geometrically constrained weak solution of the system considered independently of the type of the spatial domain or the boundary conditions. KCI Citation Count: 0
In order to achieve the reutilization of waste biomass soybean dregs, a low-cost hydrogel, soybean dregs-poly(acrylic acid) (SESD-PAA) was prepared through a one-step reaction. The synthesized ...polymer was verified by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. As an adsorbent, SESD-PAA was used to remove Zn(ii), Fe(iii), Cu(ii), and Cr(iii) from aqueous solutions. The effect of pH, initial concentration, and contact time on metal ion adsorption was examined. It was found that SESD-PAA showed high and fast adsorption capacities for Zn(ii), Fe(iii), Cu(ii), and Cr(iii), which were 121.2, 78.5, 75.4, and 41.7 mg g-1, respectively. Moreover, before and after the adsorption of these ions, the hydrogels were analyzed by X-ray photoelectron spectroscopy, which confirmed that the metal ions were adsorbed by the polymer by interactions of carboxyl, hydroxyl, and amine groups with metal ions. Additionally, the adsorption process followed a pseudo-second-order kinetics model, the Fickian diffusion model, and the Freundlich adsorption model. Furthermore, the competitive adsorption of metal ions in mixtures and the desorption/regeneration capacity of SESD-PAA were investigated. As an efficient, low-cost, easily obtained, and environmentally friendly adsorbent, SESD-PAA was expected to be used for the processing of large amounts of sewage.
•Hollow Sn-doped NiO nanofibers are synthesized through a facile electrospinning approach.•The Sn-doped NiO sensor with suitable Sn content (6 at%) shows the highest gas response to triethylamine.•Sn ...doping concentrations can significantly influence the resistance of sensors in air and in target gas under different RH.•The resistances of the sensor change slightly in target gas under different RH with suitable Sn doping content (6 at%).
High stable triethylamine gas sensors under different relative humidity are highly desirable in order to correctly detect the concentrations of target gas. In this study, a series of Sn-doped NiO hollow nanofibers were prepared through a facile electrospinning process followed by heat treatment. Sn doping could inhibit the crystal growth, and the crystal sizes would decrease with the increase of Sn doping concentration. Gas sensing investigation indicates that Sn doping could significantly enhance the gas response towards triethylamine at a relative low temperature. Especially, the gas sensor exhibits the highest response to triethylamine when the doping content of Sn reaches to 6 at%. The response value is about 16.6–100 ppm triethylamine, and it is ∼9.2 times higher than that of pure NiO nanofibers at the same operating temperature. In addition, the resistances of the gas sensors with different doping contents of Sn would change differently in air or in target gas under variable relative humidity. The resistances in target gas are almost unchanged with the increase of relative humidity with the Sn doping content of 6 at%. It is reasonable to speculate that Sn doping can heavily alter the surface state of NiO nanofibers, which is beneficial for the improvement of the gas response and humidity dependence properties.
Wastewater reuse as a sustainable, reliable and energy recovery concept is a promising approach to alleviate worldwide water scarcity. However, the water reuse market needs to be developed with ...long-term efforts because only less than 4% of the total wastewater worldwide has been treated for water reuse at present. In addition, the reclaimed water should fulfill the criteria of health safety, appearance, environmental acceptance and economic feasibility based on their local water reuse guidelines. Moreover, municipal wastewater as an alternative water resource for non-potable or potable reuse, has been widely treated by various membrane-based treatment processes for reuse applications. By collecting lab-scale and pilot-scale reuse cases as much as possible, this review aims to provide a comprehensive summary of the membrane-based treatment processes, mainly focused on the hydraulic filtration performance, contaminants removal capacity, reuse purpose, fouling resistance potential, resource recovery and energy consumption. The advances and limitations of different membrane-based processes alone or coupled with other possible processes such as disinfection processes and advanced oxidation processes, are also highlighted. Challenges still facing membrane-based technologies for water reuse applications, including institutional barriers, financial allocation and public perception, are stated as areas in need of further research and development.
β-carotene is widely available in plant-based foods, while the efficacy of β-carotene supplementation on cardiovascular disease (CVD) risk remains controversial. Hence, we performed a systematic ...review and meta-analysis on randomized controlled trials to investigate the associations between β-carotene supplementation and CVD risk as well as mortality. We conducted literature searches across eight databases and screened the publications from January 1900 to March 2022 on the topic of β-carotene treatments and cardiovascular outcomes. There were 10 trials and 16 reports included in the meta-analysis with a total of 182,788 individuals enrolled in the study. Results from the random-effects models indicated that β-carotene supplementation slightly increased overall cardiovascular incidence (RR: 1.04; 95% CI: 1.00, 1.08) and was constantly associated with increased cardiovascular mortality (RR: 1.12; 95% CI: 1.04, 1.19). Subgroup analyses suggested that, when β-carotene treatments were given singly, a higher risk of cardiovascular outcomes was observed (RR: 1.06; 95% CI: 1.01, 1.12). In addition, cigarettes smoking was shown to be a risk behavior associated with increased cardiovascular incidence and mortality in the β-carotene intervention group. In sum, the evidence of this study demonstrated that β-carotene supplementation had no beneficial effects on CVD incidence and potential harmful effects on CVD mortality. Further studies on understanding the efficacy of multivitamin supplementation in nutrient-deficient or sub-optimal populations are important for developing the tolerable upper intake level for β-carotene of different age and sex groups.
Anionic diffusion in a soft crystal lattice of hybrid halide perovskites affects their stability, optoelectronic properties and the resulting device performance. The use of two-dimensional (2D) ...halide perovskites improves the chemical stability of perovskites and suppresses the intrinsic anionic diffusion in solid-state devices. Based on this strategy, devices with an enhanced stability and reduced hysteresis have been achieved. However, a fundamental understanding of the role of organic cations in inhibiting anionic diffusion across the perovskite-ligand interface is missing. Here we demonstrate the first quantitative investigation of the anionic interdiffusion across atomically flat 2D vertical heterojunctions. Interestingly, the halide diffusion does not follow the classical diffusion process. Instead, a 'quantized' layer-by-layer diffusion model is proposed to describe the behaviour of the anionic migration in 2D halide perovskites. Our results provide important insights into the mechanism of anionic diffusion in 2D perovskites and provide a new materials platform with an enhanced stability for heterostructure integration.
Pancreatic cancer is a devastating disease that is characterized by persistent hypoxia. The roles of hypoxia-inducible factor-2α (hif-2α) are different to those of hif-1α, although both are critical ...for tumor cells to adapt to the hypoxic microenvironment. However, unlike the well-studied hif-1α, the role of hif-2α in tumors, including pancreatic cancer, is poorly understood.
Herein, we used a mutated hif-2α (A530T) to figure out the problem that wild-type hif-2α is quickly degraded which limits the study of its function. Using several cell lines, mouse models, and human tissues, we obtained a general picture of hif-2α in pancreatic cancer progression.
Functional assays revealed that hif-2α promotes epithelial-to-mesenchymal transition, enhances tumor proliferation and invasion, increases stemness, facilitates angiogenesis, and up-regulates aerobic glycolysis. We identified an interaction between hif-2α and β-catenin, and found that hif-2α/β-catenin complex formation increased the activity of β-catenin and the protein stability of hif-2α. In vivo study confirmed the pro-oncogenic role of hif-2α, whose expression correlated with those of E-cadherin, vimentin, Ki-67, and CD31, but not hif-1α. A human tissue study showed that hif-2α was associated with lymph node metastasis, pathological grade, stroma abundance, vascularization and patient survival. High expression of hif-2α was also identified as an independent indicator of poor prognosis in patients with pancreatic cancer.
Our systematic study revealed the roles of hif-2α in pancreatic cancer, and may provide a novel target for this highly malignant disease.
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